Asphalt Emulsion Basics

8/22/2019 Asphalt Emulsion Basics

1/60

EMULSION BASICS

Midwestern Pavement

reserva on ar ners p

Adam Redman

Heritage Research Group

October 28, 2010

Des Moines, Iowa


2/60

OVERVIEW

Testing Description

History

Storage

and

Handling

Production Classifications

Composition

Performance


3/60

HISTORY OF ASPHALT EMULSIONS

First developed in the 1900s

In the 20s asphalt emulsions came into general use forpaving applications

Early use was in spray applications and dust control.


4/60


Interest picked up in the 50s for farm to market roads


5/60


The environmental movement in the 1970s

prompted the increase in emulsionmanufacturing due to concerns about pollutionfrom cutback asphalts (VOCs)


6/60


New formulations have increased performance

for many applications


7/60

WHAT IS AN ASPHALT EMULSION?

Two liquids or components with onedispersed continuously through theother

together in a stable suspension with theaid of a surfactant

Examples of common emulsions areshampoo, milk, mayonnaise and paint


8/60

OIL & WATER EMULSION NOT

STABILIZED

Unstable emulsion.

Not an emulsion.


9/60

WHICH WILL COME OUT ON TOP?


10/60

OIL & WATER EMULSION STABILIZED

Oil and water canbe emulsified

a surfactant is

added.


11/60

HOW EMULSIFIERS WORK

Gives stability to the emulsion

Does not allow the Oil(asphalt) to separate from

Both cationic and anionic emulsifiers are surfactants (soaps)

the water. Gives a charge

Cationic vs. Anionic

(Positive vs. Negative) Imparts setting characteristics

Slow Set, Medium Set andQuick Set


12/60

ANIONIC EMULSIFIER STRUCTURE

CH3CH2CH2CH2

CH2CH2CH2CH2

CH2CH2CH2CH2 O

CH2CH2CH2C

Tail Group: Hydrocarbon, lipophilic(Oil loving)

COO-Na+

Head Group: Polar, hydrophilic (Water loving)


13/60

SURFACTANT MODEL

o

Tall OilSodium Hydroxide

Polar Head

(Water Loving) Non-Polar Tail

(Oil Loving Hydrocarbon)

oNa- c c c c c c


14/60

ASPHALT EMULSION MODEL

Asphalt

Droplet

Surfactant

Water


15/60

Cationic Anionic+

+

++

+++

++

++

++

++++

+++

++ +

++ -

---

---

-

--

----

--- -

--

----

---

+++ ---

+ +

Repulsion

- -

Repulsion

+ -Attraction

Never Mix Emulsions


16/60

CHEMICAL SET

- --

-

--

--

-

--

-

-

--

-

----

---

--

-

----

---

--

-- ---

- - --- -

---

-- -

--

----

--- --

----- - -

--- --

----- - -

---

-

-----

- -

--

- - ---

---

-

-

Rapid

Medium

Slow


17/60

NAMING THE EMULSIONS

Prefix RS = rapid set

SS = slow setQS = quick set

MS = medium set

=

C = Cationic

AE = anionic emulsion

Suffix 90,150, or 300 = penetration ranges h = hard penetration

P,M or L = modified with polymer or latex

1 = low viscosity, stored @ cooler temps 2= high viscosity, stored @ higher temps


18/60

NOMENCLATURE

HFRS-2

High Float Rapid Setting

High

Viscosity

-

Cationic Rapid Setting

,

Polymer Modified

CSS-1h

Cationic Slow Setting

Low Viscosity,

hard asphalt


19/60

MODIFICATIONS

Polymers

SBS & SBR Large Molecules

Increase Service Life of

the Project

Early Chip Retention

Flexibility

Elasticity


20/60

FLUORESCENCE OPTICAL

MICROSCOPE

4% SBS in Asphalt


21/60

GENERAL CLASSIFICATION

Rapid-Setting Medium-Setting

-

Quick-Setting and Micro-Surfacing


22/60

RAPID SETTING EMULSION

Designed to react quickly with aggregate andrevert from the emulsion to the asphalt.

Primaril used for s ra a lications.

RS-2, HFRS-2, MWS-90, and CRS-2


23/60

SURFACE TREATMENT APPLICATION


24/60

MEDIUM SETTING EMULSION

Designed for mixing with graded aggregate.

Formulated not to break immediately upon

contact with aggregate and will remain workable

or a ew m nu es o severa mon s epen ngupon the formulation.

Primarily used in pugmills.

MS-2, CMS-2, HFMS-2, MWS-150 & 300


25/60

COLD CONSTRUCTED ASPHALT

PAVEMENTS


26/60

SLOW-SETTING EMULSION

Designed for mixing stability.

Primarily used with high fine content

aggregates, tack coats, fog seals and

dust palliatives. SS-1h, Dustlay, Dust Control


27/60

QUICK-SETTING & MICRO SURFACING

Designed specifically for slurry and micro-

surfacing emulsions. Allows quicker opening to traffic times.

Micro-surfacing emulsions are polymermodified and allow mixes to be placed at

greater thickness than slurry seals.

CSS-1h, CQS-1h and CQS-1hM


28/60

MICRO SURFACING / SLURRY


29/60

EMULSION PRODUCTION


30/60

EMULSION MILL

Colloid Mill

Rotor & Stator


31/60

EMULSION PARTICLE SIZE

Asphalt

emulsion1-10 Micronsin size

Human Hair

70-100Microns insize


32/60

VERTICAL TANKS

Vertical storage tanks

are recommended.

Tanks should beinsulated to protect the

emulsion from freezing.

There is less surfacearea which means there

is less exposure of the

emulsion to air.

These tanks are easier

to put into place, heat,

insulate and keep track

of inventory.


33/60

STORAGE TEMPERATURES

Recommended

StorageTemperatures

Emulsion MINF MAXF

RS-1 70 140

RS-2 125 185

HFRS-2 125 185

SS-1h 50 140

manufacture for theirrecommended

storage temperatures

AE-90 125 185MS-2 125 185

CQS-1h 50 140

CSS-1hM 50 140

CRS-2 125 185

CRS-2P 125 185


34/60

STORAGE AND HANDLING

Flocculationwhen the particles

stick together.

Reasons for thismaybe due to a low

chemical load,

thermal shock, andprolonged storage.


35/60


Coalescenceparticles that stick

together become

larger. Reasons for this

maybe due to

flocculation.


36/60


Settlement the

heavier asphalt

particles settle to the

.

Reasons for this maybeprolonged storage, lack

of mixing, problems with

asphalt compatibility orwrong chemical load.


37/60

PARTICLE SIZE AFFECTS

EMULSION BREAKDOWN

Variable Size

Pack Efficiently

Same Size

Pack Poorly

Poor Packing is More Stable

and Produces Higher Viscosity


38/60

VISCOSITY IS RELATED TO QUANTITY

OF EXTERNAL PHASE AND PACKING

Low Asphalt Content

Low Viscosity

High Asphalt Content

High Viscosity


39/60

STORING ASPHALT EMULSIONS

DO store as you would water between 50F and 185F, depending on theintended use and specific product.

DO store at the temperature specified for the particular grade and

application.

DO NOT permit the asphalt emulsion to be heated above 185F. Elevatedtemperatures evaporate water, changing the characteristics of the asphaltemulsion.

DO NOT let the emulsion freeze. This breaks the emulsion, separatingthe asphalt from the water. The result will be two layers in the tank, neitherof which will be suited for the intended use.

DO NOT allow the temperature of the heating surface to exceed 212F.This will cause premature breakdown of the emulsion on the heating

surface. DO NOT use forced air to agitate the emulsion. It may cause the emulsion

to break.

- Chapter Three from the Basic Asphalt Emulsion Manual. The Asphalt Institute


40/60

HANDLING EMULSIFIED ASPHALTS

DO when heating emulsified asphalt agitate it to eliminate or reduce skin formation.

DO protect pumps, valves, and lines from freezing in winter. Drain pumps or fill themwith anti-freeze according to the manufactures recommendations.

DO blow out lines and leave drain plugs open when they are not in service. DO use pumps with proper clearances for handling emulsified asphalt. Tightly fitting

pumps can cause binding and seizing.

DO use a mild heating method to apply heat to the pump packing or casing to free a. .

DO warm the pump to about 150F (65C) to ease start-up DO when a pump is to be out of service for even a short period of time, fill it with fuel

oil to ensure a trouble free start-up.

DO before dilution grades of emulsified asphalt, check the compatibility of the waterwith emulsion (not the emulsion to the water).

DO if possible, use warm water for dilution and always add the water slowly to theemulsion (not the emulsion to the water).

DO avoid repeated pumping and recycling, if possible, as the viscosity may dropand air may become entrained, causing the emulsion to be unstable.



41/60


DO guard against mixing different classes, types, and grades of emulsified asphalt

in storage tanks, transports, and distributors. For example, if cationic and anionic

emulsified asphalts are mixed, the blend will break and separate into water and

coagulated asphalt that will be difficult to remove. Because it is hard to determine

visually the difference between various emulsified asphalts, always make a trial

blend of the newly-delivered emulsion and the stored emulsion before pumping off.

Check the trial blend for compatibility.

DO place inlet pipes and return lines at the bottom of tanks to prevent foaming.

DO pump from the bottom of the tank to minimize contamination from skinning that

may have formed.

DO rememberthat emulsions with the same grade designation can be very

different chemically and in performance.

DO haul emulsion in truck transports with baffle plates to prevent sloshing. DO mix by circulation, or otherwise, emulsions that have been in prolonged

storage.



42/60


DO NOT use tight-fitting pumps for pumping emulsified asphalt; they may

seize or shear the asphalt emulsion.

DO NOT apply severe heat to pump packing glands or pump casing. Thepump may be damaged and the asphalt may become even harder.

DO NOT dilute rapid-setting grades of emulsified asphalt with water.

Medium and slow setting grades may be diluted, but always add water

slowly to the asphalt emulsion. Never add the asphalt emulsion to a tank

of water when diluting.

DO NOT re-circulate emulsified asphalts for too many cycles. They tend

to lose viscosity when subjected to excessive pumping. Also, air bubbles

may become entrained which would render the emulsion unstable.

DO NOT load emulsified asphalt into storage tanks, tank cars, tanktransports, or distributors containing remains of incompatible materials.



43/60

WHY IS PROPER STORAGE AND

HANDLING SO IMPORTANT?

Quality of the emulsion

Performance and application of the

emulsion.

COST!!!


44/60

TESTING OF EMULSIONS

Composition

Particle Charge Density

Distillation

Reactivity

Demulsibility

Residue Tests

Storage and Handling Storage Stability

Sieve

Saybolt Viscosity

Float Test Penetration

Dynamic Shear

Rheometer

PARTICLE CHARGE TESTER


45/60

PARTICLE CHARGE TESTER

Used to identify the

charge of the

emulsion.

Cationic (positive)

Anionic (negative) Non-ionic (no charge)

ASTM D 244

SAYBOLT FUROL VISCOSITY


46/60

SAYBOLT FUROL VISCOSITY

Measure the viscosity

of the emulsion. Test temperatures are

25C and 50C.

Viscosity is defined asa fluids resistance to

flow.

ASTM D 244


47/60

STORAGE STABILITY

Indicates an emulsions

stability in storage. Sample is taken from the

top and bottom after

24hrs.

Residues can only differ

by less than 1.0%.

ASTM D 6930

OVERSIZED PARTICLES IN


48/60

EMULSIFIED ASPHALT

(Sieve Test)

Test to measure thequality of an emulsion

Excessive amounts of

sieve (>0.1%)indicate emulsion

instability.

ASTM D 6933

DEMULSIBILITY


49/60

DEMULSIBILITY

Test indicates the relative

rate at which the colloidal

asphalt particles in anemulsion will break when

mixed or s read on

aggregate. Determines if the

emulsion is rapid or slow

setting.

ASTM D 6936

EMULSION DENSITY


50/60

EMULSION DENSITY

Determines thedensity or weight per

gallon on theemulsion.

change depending onthe asphalt content.

Used for billing and

inventory purposes. ASTM D 6937

DISTILLATION


51/60

DISTILLATION

Used to separate thewater from the

asphalt. Measures the amount

emulsion. Additional tests are

run on the residue

that is recovered. ASTM D 6997

Float Test


52/60

Float Test

Measures the

resistance to flow at

elevated

empera ures .

Float test is used for

high float emulsions.

ASTM D 139-95

PENETRATION


53/60

PENETRATION

Used to determined

the hardness of the

asphalt.

ASTM D 5-05

RING and BALL


54/60

RING and BALL

Measures thesoftening point

properties of anasphalt or emulsion

.

First developed forthe roofing andwaterproofing

industry. ASTM D 36

DYNAMIC SHEAR RHEOMETER


55/60

DYNAMIC SHEAR RHEOMETER

Measures the

rheological properties

of an asphalt or

emu s on res ue.

Developed for PG

testing of asphalt

binders

SUMMARY WHY USE EMULSIONS


56/60

SUMMARY WHY USE EMULSIONS

Emulsions reduce apparent viscosity of

product Allow application temperature to be

Reduces application rate necessary to

achieve coating on a surface

To improve adhesion by chemicallyattracting emulsion droplets to surface

using charge

DONT WANT FAILURES


57/60

DON T WANT FAILURES

WANT SUCCESSFUL PROJECTS


58/60

WANT SUCCESSFUL PROJECTS

CONCLUSION


59/60

CONCLUSION

The better that the materials are

understood the better they can be used fortheir intended purpose

pavements

Use the resources of your emulsion

supplier to achieve success in roads

THANK YOU


60/60

THANK YOU

Adam RedmanHeritage Research Group7901 W Morris Street

Indianapolis, IN 46231

[email protected](317) 390-3631

Documents

Asphalt Emulsion Basics